Re: [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor

[Fabiano Rosas <farosas@linux.ibm.com>]

Nicholas Piggin <npiggin@gmail.com> writes:

> The spapr virtual hypervisor does not require the hdecr timer.

Why is that? Is this not needed for an emulated powernv running KVM
guests?

> Remove it.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  hw/ppc/ppc.c            | 2 +-
>  hw/ppc/spapr_cpu_core.c | 6 +++---
>  2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
> index 462c87dba8..a7c262db93 100644
> --- a/hw/ppc/ppc.c
> +++ b/hw/ppc/ppc.c
> @@ -1072,7 +1072,7 @@ clk_setup_cb cpu_ppc_tb_init (CPUPPCState *env, uint32_t freq)
>      }
>      /* Create new timer */
>      tb_env->decr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_decr_cb, cpu);
> -    if (env->has_hv_mode) {
> +    if (env->has_hv_mode && !cpu->vhyp) {
>          tb_env->hdecr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_hdecr_cb,
>                                                  cpu);
>      } else {
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index a781e97f8d..ed84713960 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -261,12 +261,12 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr,
>          return false;
>      }
>  
> -    /* Set time-base frequency to 512 MHz */
> -    cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
> -
>      cpu_ppc_set_vhyp(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
>      kvmppc_set_papr(cpu);
>  
> +    /* Set time-base frequency to 512 MHz. vhyp must be set first. */
> +    cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
> +
>      if (spapr_irq_cpu_intc_create(spapr, cpu, errp) < 0) {
>          qdev_unrealize(DEVICE(cpu));
>          return false;